Custom data indicating nominal range of samples of media content

Abstract

A media processing tool adds custom data to an elementary media bitstream or media container. The custom data indicates nominal range of samples of media content, but the meaning of the custom data is not defined in the codec format or media container format. For example, the custom data indicates the nominal range is full range or limited range. For playback, a media processing tool parses the custom data and determines an indication of media content type. A rendering engine performs color conversion operations whose logic changes based at least in part on the media content type. In this way, a codec format or media container format can in effect be extended to support full nominal range media content as well as limited nominal range media content, and hence preserve full or correct color fidelity, while maintaining backward compatibility and conformance with the codec format or media container format.

We claim: 
     
       1. One or more computer-readable media having stored thereon computer-executable instructions for causing a computing system, when programmed thereby, to perform video processing operations, wherein the one or more computer-readable media are selected from the group consisting of volatile memory, non-volatile memory, magnetic disk, CD-ROM, and DVD, the video processing operations comprising:
 determining range data for encoded video content, wherein the range data indicates nominal range of samples of the encoded video content as video content type for input video to encoding, the samples of the encoded video content having a sample depth that indicates an available range of values of the samples of the encoded video content, wherein the nominal range is a range of values, within the available range for the sample depth of the samples of the encoded video content, for the video content type, and wherein the range data indicates one of multiple possible options for the nominal range, the multiple possible options for the nominal range including:
 full range characterized by values from 0. . . 2 n −1 for samples of bit depth n; and 
 a limited range characterized by values in a sub-range of the full range; and 
 
 outputting the range data and the encoded video content. 
 
     
     
       2. The one or more computer-readable media of  claim 1 , wherein the range data is signaled as one or more syntax elements in an elementary video bitstream that also includes syntax elements for the encoded video content. 
     
     
       3. The one or more computer-readable media of  claim 2 , wherein the video processing operations further comprise:
 receiving an indication of the video content type provided by a video source; 
 receiving the input video from the video source; and 
 producing the elementary video bitstream, wherein the one or more syntax elements for the range data are signaled during the producing based on the video content type. 
 
     
     
       4. The one or more computer-readable media of  claim 1 , wherein the range data is signaled as part of data for an entry point in an elementary video bitstream, the entry point being a group of frames. 
     
     
       5. The one or more computer-readable media of  claim 1 , wherein the range data is a Boolean value that indicates whether the nominal range is the full range or the limited range. 
     
     
       6. The one or more computer-readable media of  claim 5 , wherein the full range is 0. . .255 and the limited range is 16. . .235. 
     
     
       7. The one or more computer-readable media of  claim 5 , wherein the encoded video content is in a YUV format, the full range is YUV 0. . .255, and the limited range is YUV 16. . .235. 
     
     
       8. The one or more computer-readable media of  claim 1 , wherein the nominal range of the samples of the encoded video content is part of a format of the samples of the encoded video content. 
     
     
       9. In a computing system that implements a video processing tool, a method comprising:
 receiving range data and encoded video content, wherein the range data indicates nominal range of samples of the encoded video content as video content type for reconstructed video output of decoding, the samples of the encoded video content having a sample depth that indicates an available range of values of the samples of the encoded video content, wherein the nominal range is a range of values, within the available range for the sample depth of the samples of the encoded video content, for the video content type, and wherein the range data indicates one of multiple possible options for the nominal range, the multiple possible options for the nominal range including:
 full range characterized by values from 0. . . 2 n −1 for samples of bit depth n; and 
 a limited range characterized by values in a sub-range of the full range; 
 
 parsing the range data; and 
 decoding the encoded video content. 
 
     
     
       10. The method of  claim 9 , wherein the range data is signaled as one or more syntax elements in an elementary video bitstream that also includes syntax elements for the encoded video content. 
     
     
       11. The method of  claim 10 , further comprising:
 providing, based on the parsed range data, an indication of the video content type; and 
 performing color conversion operations on the samples of the encoded video content, wherein logic for the color conversion operations changes based at least in part on the video content type. 
 
     
     
       12. The method of  claim 9 , wherein the range data is signaled as part of data for an entry point in an elementary video bitstream, the entry point being a group of frames. 
     
     
       13. The method of  claim 9 , wherein the range data is a Boolean value that indicates whether the nominal range is the full range or the limited range. 
     
     
       14. The method of  claim 13 , wherein the full range is 0. . .255and the limited range is 16. . .235. 
     
     
       15. The method of  claim 13 , wherein the encoded video content is in a YUV format, the full range is YUV 0. . .255, and the limited range is YUV 16. . .235. 
     
     
       16. The method of  claim 9 , wherein the nominal range of the samples of the encoded video content is part of a format of the samples of the encoded video content. 
     
     
       17. One or more computer-readable media having stored thereon computer-executable instructions for causing a computing system, when programmed thereby, to perform video processing operations, wherein the one or more computer-readable media are selected from the group consisting of volatile memory, non-volatile memory, magnetic disk, CD-ROM, and DVD, the video processing operations comprising:
 receiving range data and encoded video content, wherein the range data indicates nominal range of samples of the encoded video content as video content type for reconstructed video output of decoding, the samples of the encoded video content having a sample depth that indicates an available range of values of the samples of the encoded video content, wherein the nominal range is a range of values, within the available range for the sample depth of the samples of the encoded video content, for the video content type, and wherein the range data indicates one of multiple possible options for the nominal range, the multiple possible options for the nominal range including:
 full range characterized by values from 0. . . 2 n −1 for samples of bit depth n; and 
 a limited range characterized by values in a sub-range of the full range; 
 
 parsing the range data; and 
 decoding the encoded video content. 
 
     
     
       18. The one or more computer-readable media of  claim 17 , wherein the range data is signaled as one or more syntax elements in an elementary video bitstream that also includes syntax elements for the encoded video content. 
     
     
       19. The one or more computer-readable media of  claim 17 , wherein the range data is signaled as part of data for an entry point in an elementary video bitstream, the entry point being a group of frames. 
     
     
       20. The one or more computer-readable media of  claim 17 , wherein the range data is a Boolean value that indicates whether the nominal range is the full range or the limited range.